●Description This is the basic application for connecting and communicating with a Bluetooth(R) v4.0 enabled G-SHOCK. Pairing the watch with your smartphone enables use of a variety of different Mobile Link functions that greatly enhance the smartphone experience. The GBA-400+ app also simplifies certain watch operations by letting you perform them on your phone screen. Visit the website below for details. http://world.g-shock.com/ We recommend using GBA-400+ on the following operating systems. Operation is not guaranteed for any operating system not listed below. Even if an operating system has been confirmed as compatible, software updates or display specifications may prevent proper display and/or operation. GBA-400+ cannot be used on Android feature phones with arrow keys. ⋅ Android 6.0 or later. Please refer to the FAQ link below to resolve problems such as being unable to connect or operate the watch. https://support.casio.com/en/support/faqlist.php?cid=009001019 Supported G-SHOCK Models: GBA-400